AN UPDATE: Searching for aphids that feed on ferns

I have started to look into getting fern aphids, or aphids that are able of feeding from ferns. However, I cannot see any on the ferns that grow around this area (in Germany)! An alternative solution would be to find a non-fern aphid that can feed from the fern phloem. As you know from my introductory video, it is only when aphids are in phloem-feeding phase, that they can be used as living electrodes.

In my surroundings, I see a black aphid infesting many different plants (Amaranthus, Papaver), which means that it is a generalist species (that is, non specialized for a particular type of plant). Therefore, perhaps they don't mind to feed from ferns. To check for this possibility, I wired them for Electrical Penetration Graph recordings. Surprisingly, this black aphid pokes into the fern leaves and shows a "normal" Electrical Penetration Graph pathway phase. However, these black aphids never went into a phoem-feeding phase on ferns. During the pathway phase, they moved their flexible stylets between cells, poking cells for brief periods of time. Eventually, when the sylet pokes into a phloem cell (called "sieve element"), it does not take it out, but keeps it inserted for long periods of time (for hours!), as it feeds from the sap that flows through the sieve element. As I said, this never happened for these black aphids when they were put on the ferns.

In a parallel experiment, I put several of these black aphids on ferns, and left them overnight. The next day, they were still attacked to the fern, but they were dead. It is as if they looked and looked for the phloem but could not find it... or could not recognize it!

Find below a detail showing two punctures in two cells of the fern leaf, lasting just a few seconds each. The x-axes represents time, and the y-axes represents voltage.